The present invention represents an improvement on mine ventilation panel systems of the type described in U.S. Pat. Nos. 2,729,064, 4,483,642, 4,547,094 (reissued as Re. 32,871), 4,695,035, 4,820,081, 5,167,474, 5,412,916, 5,466,187, 6,220,785 and 6,264,549, all of which are incorporated herein by reference in their entireties. These prior systems have been used to make various mine ventilation structures, such as stoppings, overcasts and undercasts. The use of these systems have been widespread and successful in improving mine ventilation. For a discussion of the principles of mine ventilation, the practical application of such principles to mining ventilation problems, and the structures used to achieve proper ventilation in a mine, reference may be made to the book entitled “Practical Mine Ventilation” by William R. Kennedy, co-inventor of the improved panel system described herein for making such structures. This book is incorporated herein by reference for all purposes.